The present invention relates to a digital signal recording system for recording digital signals on a video tape, and, more particularly; to a digital signal recording system for converting composite TV signals into a digital component signals or receiving digital component signals directly input from outside of the system to inside of the system and for recording the digitally converted digital component signals or the directly input digital component signals on a video tape.
Generally, in the field of a video cassette tape recorders, recording technology using high definition and high density recording systems has been under development for a long time. In order to obtain a picture quality with a high definition, a digital signal recording system is preferable to an analog signal recording system in view of picture quality and an edit of the picture image. An existing analog composite NTSC signal is composed of a luminance signal with 320 lines and a chrominance signal with 120 to 40 lines, while a video signal utilized in the recently developed digital recording system is composed of a luminance signal of 520 lines and a chrominance signal of 260 lines in order to code the video signal in accordance with the international standard. Accordingly, the digital component recording method is adapted to a digital signal recording system.
In a conventional digital video cassette tape recorder(hereinafter referred to VCR), analog type video and audio signals are converted into digital signals, and then the digitally converted signals are inputted to a digital signal processor. This digital signal processor compresses data transmission bit rates because the amount of the digitally converted data input thereto is too numerous. The digital signal processor also codifies the digital data for correcting errors.
Error corrected data are recorded on the magnetic tape by a magnetic head through a modulation process, that is, a recording codification process.
In order to realize a digital VCR for use at home with the above-described principle, three technologies are required as follows: First, a high density recording technology for decreasing an occupying area per bit on a tape, second, a compression technology of the data transmission bit rate for decreasing an amount of picture image data to be recorded, and third, a technology for improvement of a recording medium. However, in realizing the above-described technologies, there have been notable defects; that is if a recording density is heightened, an error ratio is increased and if a picture compression degree is increased, a picture quality is degraded.
Thus, in a technological field to which the present invention is adapted, a variety of recording systems have been developed as means for realizing the fundamental functions described above because the characteristics of the recording system rely upon a means embodying the above-described fundamental functions in a digital signal recording system.